1. Field of the Invention
The present invention is in the field of compact dust collectors.
2. Description of the Prior Art
Industrial processes and combustion of solid fuel often result in the suspension of potentially hazardous particulate matter in the air. Consequently, in many industries, systems for filtering air or other gases are required.
As described in U.S. Pat. No. 4,395,269 to Schuler, early systems for meeting these filtering needs were often bulky, difficult to install, and subject to damage and rapid wear. Schuler discloses an effort to meet the industry need for a more compact and more efficient air filtration system. The air filtering system in Schuler has a housing which includes an uppermost portion, and a lowermost portion which is commonly known as the hopper of a dust collector. Cylindrical filter elements are mounted in an inclined direction within the housing upon an interior wall of stepped construction. Accordingly, to provide convenient access to the filter elements from points exterior of the housing, the exterior wall against which the opposite ends of the filter elements fall must also be of stepped construction. A stepped wall is more difficult and more expensive to construct than a flat wall contained in a single plane.
The filter elements in Schuler are mounted almost entirely within the uppermost portion of the housing resulting in a large volume of non-utilized space within the same. Thus, the housing may be more capacious than it need be. Additionally, Schuler discloses filter elements arranged in rows, wherein filter elements in lower rows are vertically aligned with filter elements in upper rows. Consequently, contamination of lower filter elements is increased by particulate matter falling from vertically aligned upper filter elements, as when the pulse jet cleaning means are operated. Schuler discloses a system designed to reduce this effect which contemplates pulse jet cleaning uppermost filter elements first, with the cleaning of the remaining filter elements occurring from top to bottom in the assembly. However, this system does not completely eliminate increased contamination of lower filter elements because they are nevertheless subjected to greatly increased impingement by particulate matter. Additionally, such a pulse jet cleaning system is more complex and more expensive than a system which pulse jet cleans all filter elements simultaneously.
U.S. Pat. No. 4,509,960 to Engel discloses an invention directed to a dust collector. The dust collector of Engel is generally more complex than the air filtering assembly of Schuler. Nevertheless, it also includes a housing having an uppermost portion and a lowermost hopper portion. The filter elements of Engel are of a rectangular construction, and like the filter elements of Schuler, are mounted substantially within the uppermost portion of the housing, with lower filter elements being vertically aligned with filter elements within a row immediately above. Another similarity between the disclosures of Schuler and Engel is that their entrance and exit openings occur at differing elevations. Thus, to modularize a number of dust collectors to direct air through successive dust collectors, thereby more completely filtering air, one would need elevatory adjustment means, such as a contoured pipe, between the exit opening of one dust collector and the entrance opening of another. Such adjustment means are both bulky and expensive.
The inventor also has knowledge of dust collectors manufactured by Torit division of the Donaldson Company. Specifically, these are models 2DF8, 2DF12, 2DF16, 3DF24, 3DF36, 3DF60, 3DF72, 4DF32, 4DF48, 4DF64, 4DF80. These dust collectors are strikingly similar to the air filtering system disclosed in Schuler. Generally, these models include housings having uppermost portions and lowermost hopper portions. Cylindrically shaped filter elements are mounted therein upon walls of stepped construction. Further, the filter elements are mounted in an inclined direction and substantially within the uppermost portions of the dust collectors. Additionally, the filter elements are arranged wherein lower filter elements are vertically aligned with filter elements in rows immediately thereabove, and their entrance openings and exit openings occur at different elevations. Some of the above models include a number of individual dust collector units in tandem to enable the filtration of larger volumes of air, which is not to be confused with modularizing a number of dust collectors to direct air sequentially through them thereby more completely filtering the same.
In light of the inventions disclosed in Schuler, Engel, and the above Torit models, there exists a continued need for a dust collector of an even more compact construction, and of a design incorporating filter elements mounted in a space efficient inclined position, yet eliminating the need of having walls of stepped construction. An improved design would also minimize filter element contamination resulting from the pulse jet cleaning operation, and enable modularization of a number of dust collectors without elevatory adjustment means.